CN106120850A - A kind of method for designing of ballastless track of high-speed railway stake plate type retaining wall - Google Patents

Abstract

The method for designing of a kind of ballastless track of high-speed railway stake plate type retaining wall, to efficiently solve the control problem of the pile body anchoring section foundation soil lateral deformation time effect that cannot consider in a plate type retaining wall traditional design method.Carry out as follows: survey means by ground and obtain the undisturbed soil sample of design work point foundation soil, carry out indoor triaxial test record soil sample intensity index c andCarry out indoor long-term triaxial test simultaneously and record the state threshold parameter lambda that fast and stable state is corresponding；It is calculated state strength parameter c of foundation soil before stake according to gained state threshold parameter lambda¹WithIt is calculated the lateral bearing capacity σ of foundation soil deformation state before stake according to gained state strength parameter_p ¹；Draft anchor pile sectional dimension and anchoring depth by traditional anchor pile design and calculation method, calculate anchor pile to ground earth lateral pressure σ before stake_y；The relatively σ at below ground 1/3 anchoring depth_yWith σ_p；Carry out the Reinforcement Design of anchor pile, complete design flow process.

Description

A kind of method for designing of ballastless track of high-speed railway stake plate type retaining wall

Technical field

Patent of the present invention relates to the method for designing of a kind of ballastless track of high-speed railway stake plate type retaining wall.Belong to Geotechnical Engineering to prop up Gear structure-design technique field.

Background technology

Stake plate type retaining wall is to utilize the anchoring section being anchored in ground to provide skid resistance opposing to fill out earth lateral pressure, and it is main Wall is high not by the limitation in height of general barricade to want advantage to be, cantilever segment may be up to 15m, foundation bearing capacity can not pass through anchor completely Gu the buried depth of section is compensated for.But, when anchor pile cantilever segment is longer, the lateral deformation that pile body anchoring section is small will be in stake Being exaggerated at top, if the soil body and barricade generation compatible deformation after wall, then the lateral deformation of barricade will certainly cause the additional of embankment Sedimentation.When pile plate wall be applied to ballastless track of high-speed railway embankment prop up gear time, it is desirable to the deformation of anchoring section foundation soil is in quickly Steady statue (deformation is without time effect), controls the additional settlement of roadbed, to meet non-fragment orbit putting down under the conditions of few maintenance Pliable requirement.China TB10025-2006 " railway bed retaining structure design specification " specifies: pile plate wall below ground anchoring section Resistant force in front of anti-sliding pile at length 1/3 should be not more than foundation soil horizontal permitted bearing capacity [σ_H], and require that the lateral displacement of stake top is less than outstanding The 1% of arm segment length, and no more than 100mm.The deformation state of this intensity and Bit andits control standard and anchoring section foundation soil " fast and stable " state of requirement is not mated, it is difficult to the requirement of high-speed railway under the conditions of adaptation non-fragment orbit.Therefore, research It is applicable to the peg board formula DESIGN OF RETAINING WALLS method that ballastless track of high-speed railway controls based on deformation state, is high-speed railway subgrade work The key technical problem that Cheng Jianshe is urgently to be resolved hurrily.

Patent of invention content

The main purpose of patent of the present invention is to provide the method for designing of a kind of ballastless track of high-speed railway stake plate type retaining wall, During to efficiently solve the pile body anchoring section foundation soil lateral deformation that cannot consider in a plate type retaining wall traditional design method Between the control problem of effect.

It is as follows that the present invention solves the technical scheme that above-mentioned technical problem used:

The method for designing of a kind of ballastless track of high-speed railway stake plate type retaining wall of the present invention, is carried out as follows:

(1) survey means with passing through and obtain the undisturbed soil sample of design work point foundation soil, carry out indoor triaxial test and record soil Intensity index c of sample andCarry out indoor long-term triaxial test simultaneously and record the state threshold parameter lambda that fast and stable state is corresponding, When unconditionally carrying out indoor long-term triaxial test, λ takes 15%；

(2) it is calculated state strength parameter c of foundation soil before stake according to gained state threshold parameter lambda¹WithCalculate public affairs Formula is:

In formulaFoundation soil is in state strength parameter during the first state, internal friction angle, °；

c¹Foundation soil is in state strength parameter during the first state, cohesion, kPa；

Foundation soil actual strength parameter, internal friction angle, °；

C foundation soil actual strength parameter, cohesion, kPa；

λ₁It is in state threshold parameter during the first state；

(3) it is calculated the lateral bearing capacity σ of foundation soil deformation state before stake according to gained state strength parameter_p ¹, calculate Formula is:

σ in formula_p ¹Foundation soil is in lateral bearing capacity during the first state, kPa；

The severe of γ foundation soil, kN/m³；

Y is away from the earth's surface degree of depth, m；

(4) draft anchor pile sectional dimension and anchoring depth by traditional anchor pile design and calculation method, calculate anchoring Stake is to ground earth lateral pressure σ before stake_y；

(5) σ at below ground 1/3 anchoring depth is compared_yWith σ_p ¹If, σ_y≤σ_p ¹Before showing stake, foundation soil is at anchor pile Effect under do not have the deformation having time effect, can carry out next step design calculate；If σ_y>σ_p ¹Shi Zexu adjusts between stake Away from or the parameter such as sectional dimension of stake recalculate, until meeting σ_y≤σ_p ¹；

(6) Reinforcement Design of anchor pile, complete design flow process are carried out.

The invention has the beneficial effects as follows, before controlling stake, foundation soil has the lateral deformation of time effect, builds new The pile plate wall method for designing of type, the shortcoming overcoming traditional design method, the requirement of ballastless track of high-speed railway can be met.

Accompanying drawing explanation

Fig. 1 is deformation state intensive parameter calculation diagram；

Fig. 2 is work point cross-sectional view；

Fig. 3 is that anchor pile is to foundation soil lateral stress scattergram；

Fig. 4-1 is anchoring section shearing scattergram；

Fig. 4-2 is anchoring section Bending moment distribution figure；

Fig. 5 is foundation soil lateral stress σ before stake_yTry hard to deformation state carrying.

Detailed description of the invention

Below in conjunction with detailed description of the invention, patent of the present invention is described in further detail.

When ballastless track of high-speed railway is by sloped ground, often building retaining structure in descending side, pile plate wall is For one of conventional selection.But, post-construction settlement of subgrade value is required extremely strict by ballastless track of high-speed railway, i.e. requires roadbed Sedimentation and deformation under Gravitative Loads and High-speed Train Loads has no time effect.It is therefore desirable to pile plate wall can not produce sometimes Between the lateral deformation of effect.Traditional pile plate wall method for designing is to ensure that retaining structure stabilizes to core purpose, does not control Whether structure there will be the lateral deformation having time effect.This is by the control technique of settlement after construction band for ballastless track of high-speed railway roadbed Carry out hidden danger.Patent of the present invention foundation soil before controlling stake has the lateral deformation of time effect, builds novel pile plate wall Method for designing, the shortcoming overcoming traditional design method, meet the requirement of ballastless track of high-speed railway.

It is critical only that of lateral deformation time effect controlling non-fragment orbit stake plate type retaining wall controls pile body anchoring location The lateral pressure of pile body suffered by foundation soil not can exceed that the load level threshold value corresponding to soil layer " fast and stable " state itself, This threshold value can be expressed with the percentage ratio of ultimate load level (peak load level).For design work point, surveyed by ground Means obtain the undisturbed soil sample of work point foundation soil, carry out indoor triaxial test and record the intensity index of soil sample, carry out interior length Phase triaxial test records the state threshold parameter lambda that " fast and stable " state is corresponding, and substantial amounts of actual measurement shows the " the most steady of fine grained soil Calmly " the state threshold parameter lambda that state is corresponding is generally 15%, i.e. pile body anchoring section acts on the lateral pressure of soil layer less than soil Layer lateral extreme bearing capacity (maximum lateral load level) 15% time, the lateral deformation of foundation soil is in fast and stable shape State, does not have time effect, meets the requirement of ballastless track of high-speed railway.It is calculated stake according to gained state threshold parameter lambda State strength parameter c of front foundation soil¹WithThe determination of soil deformation state strength parameter is according to Mohr-Column criterion, right Ultimate load carries out reduction by load level threshold value λ, thus obtain the soil deformation state corresponding with load level threshold value Intensive parameter c¹WithCalculation diagram is as shown in Figure 1.

In Fig. 1, solid line represents Mohr-Coulomb shear-resistant intensity, dotted line represent by load level reduction after soil deformation State strength line, by geometrical relationship, can derive intensive parameter c of soil deformation state¹With

Can be converted by above-mentioned formula and obtain formula:

According to gained state strength parameter c¹WithIt is calculated the lateral bearing capacity σ of foundation soil deformation state before stake_p ¹, meter Calculation formula is

Draft anchor pile sectional dimension and anchoring depth by traditional anchor pile design and calculation method again, calculate anchor pile To ground earth lateral pressure σ before stake_y.Relatively at below ground 1/3 anchoring depth, (at this, pile body gives the lateral of foundation soil Pressure is maximum) σ_yWith σ_p ¹.If σ_y≤σ_p ¹Before the bright stake of segment table, foundation soil does not haves under the effect of anchor pile time effect Deformation, can carry out next step design calculate；If σ_y>σ_p ¹Shi Zexu adjusts the parameters such as the sectional dimension of pile spacing or stake again Calculate, until meeting σ_y≤σ_p ¹.Then the Reinforcement Design complete design flow process of anchor pile is carried out.

Deriving according to above, the method for designing of a kind of ballastless track of high-speed railway stake plate type retaining wall of the present invention, by such as Lower step is carried out:

(1) survey means with passing through and obtain the undisturbed soil sample of design work point foundation soil, carry out indoor triaxial test and record soil Intensity index c of sample andCarry out indoor long-term triaxial test simultaneously and record the state threshold parameter lambda that fast and stable state is corresponding (referring to that under load action, the deformation of soil sample is quickly stable, extends and sustainable development the most in time, i.e. deforms and do not have time effect) Corresponding state threshold parameter lambda, when unconditionally carrying out indoor long-term triaxial test, λ takes 15%, i.e. soil body bearing load is less than Maxium load value 15% time its deformation will be in fast and stable state；

(2) it is calculated state strength parameter c of foundation soil before stake according to gained state threshold parameter lambda¹

WithComputing formula is:

In formulaFoundation soil is in state strength parameter during the first state, internal friction angle, °；

c¹Foundation soil is in state strength parameter during the first state, cohesion, kPa；

Foundation soil actual strength parameter, internal friction angle, °；

C foundation soil actual strength parameter, cohesion, kPa；

λ₁It is in state threshold parameter during the first state；

(3) it is calculated the lateral bearing capacity σ of foundation soil deformation state before stake according to gained state strength parameter_p ¹, calculate Formula is:

σ in formula_p ¹Foundation soil is in lateral bearing capacity during the first state, kPa；

The severe of γ foundation soil, kN/m³；

Y is away from the earth's surface degree of depth, m；

(4) draft anchor pile sectional dimension and anchoring depth by traditional anchor pile design and calculation method, calculate anchoring Stake is to ground earth lateral pressure σ before stake_y；

(5) σ at below ground 1/3 anchoring depth is compared_yWith σ_p ¹If, σ_y≤σ_p ¹Before showing stake, foundation soil is at anchor pile Effect under do not have the deformation having time effect, can carry out next step design calculate；If σ_y>σ_p ¹Shi Zexu adjusts between stake Away from or the parameter such as sectional dimension of stake recalculate, until meeting σ_y≤σ_p ¹；

(6) Reinforcement Design of anchor pile, complete design flow process are carried out.

Embodiment

1, parameter is calculated

Certain ballastless track of high-speed railway work point, as shown in Figure 2.Rolling earth behind retaining wall is A, B group filler, unit weight γ₁=23kN/m³,(equivalent friction angle)；In the range of anchor pile anchoring section, foundation soil has two-layer composition, and ground floor is that opaque sticks Soil, thickness h_2-1≈ 10m, natural unit weight γ_2-1=18.7kN/m³, c₂=40.3kPa,Liquidity index I_L=0.1； The second layer is severely-weathered shale, saturation, thickness h_2-2=6m, by ground floor soil under 0.95 compactness and saturation Under parameter value, i.e. γ_2-2=19.8kN/m³, its mechanics parameter is less with ground floor soil difference, for convenience of calculating, and this layer of soil Physical and mechanical parameter and ground floor soil take identical value, but coefficient of subgrade reaction is with the proportionality coefficient m value relatively ground floor soil of change in depth Can properly increase.Tentatively draft anchor pile cantilever segment height h₁=8m, anchoring section degree of depth h₂=16m.

Before stake, coefficient of subgrade reaction presses TB10023-1006 " railway bed retaining structure design with the proportionality coefficient m of change in depth Specification " value, as listed in table 1.Tentatively drafting anchor pile cross section is rectangle, wide B=2m, depth of section 3m, and pile body is C35 steel Reinforced concrete pours and forms, bending rigidity EI ≈ 1.4 × 10⁸kN·m², pile center's spacing L=5m.

Table 1 coefficient of subgrade reaction is with the proportionality coefficient m reference value of change in depth

According to GB50021-2001 " Code for investigation of geotechnical engineering " (2009 revised edition), ground silty clay liquidity index 0 < I_LWhen=0.1≤0.25, for hard plastic state, then coefficient of subgrade reaction is with the proportionality coefficient m of change in depth₁Span be 2000～ 4200kN/m⁴, during calculating, take its meansigma methods, then m₁=3100kN/m⁴, for severely-weathered shale, m relatively silty clay improves one grade Value, i.e. m₂Span is 3000～7000kN/m⁴, during calculating, take its meansigma methods, then m₂=5000kN/m⁴.According to specification, Anchoring section h₂In the range of soil conversion m value be:

$\begin{array}{c}m=\frac{m_1{h}_{2-1}^2+m_2\left(2h_{2-1}+h_{2-2}\right)h_{2-2}}{h_2^2}=\frac{3100\&times;{10}^2+5000\&times;\left(2\&times;10+6\right)\&times;6}{{16}^2}\&ap;4258\\ kN/m^4\end{array}$

The horizontal λ of deviatoric stress takes 0.15 according to result of the test, can obtain according to formulac₂ ¹, as listed in table 2.

The deformation state intensive parameter of table 2 deviatoric stress horizontal λ 1 correspondence

2, process and result are calculated

A) Wall back pressure

Bright gold coefficient of active earth pressure k_a1=0.2, can obtain:

$E_1=E_a=\frac{1}{2}{\mathrm{\&gamma;}}_1{h}_1^2{k}_{a1}=0.5\&times;23\&times;8^2\&times;0.2=147.2kN/m$

B) rigid pile and the judgement of elastic pile

Determination methods according to TB10023-1006 " railway bed retaining structure design specification ", rigid pile and elastic pile For:

In formula: the deformation coefficient of α stake, m^-1；

The anchorage depth of h stake, m；

The proportionality coefficient of m foundation soil horizontal resist forces, kN/m⁴；

B_pThe calculating width of stake, m；B_p=B+1；

The width of B stake, m；

The elastic modelling quantity of E stake, kPa；

The cross sectional moment of inertia of I stake, m⁴。

Then according to calculating parameter, can obtain:

$\mathrm{\&alpha;}=\sqrt[5]{\frac{{\mathrm{mB}}_p}{EI}}=\sqrt[5]{\frac{4258\&times;(2+1)}{1.4\&times;{10}^8}}=0.155m^{-1};$

αh₂=0.155 × 16=2.48 < 2.5, belongs to rigid pile.

C) anchor pile internal force calculates

Center of rotation y0 of anchor pile and anchor pile corner φ:

$y_0=\frac{h_2(9h_2+4h_1)}{6(h_1+2h_2)}=\frac{16\&times;(9\&times;16+4\&times;8)}{6\&times;(8+2\&times;16)}=11.7m;$

$\mathrm{\&phi;}=\frac{12E_{1}L(h_1+2h_2)}{B_p{\mathrm{mh}}_2^4}=\frac{12\&times;147.2\&times;5\&times;(8+2\&times;16)}{(2+1)\&times;4258\&times;{16}^4}=4.2\&times;{10}^{-4}rad.$

Anchoring section away from ground y depth anchor pile to foundation soil lateral stress σ_yFor:

σ_y=my (y₀-y) φ=4258 × 4.2 × 10^-4× (11.7-y) y=21y-1.8y²

Then anchor pile is to foundation soil maximum lateral stress σ_ymax=61.2kPa, corresponding y=5.8m, divide along the anchoring section degree of depth Cloth is as shown in Figure 3.

Anchor pile anchoring section shearing and Bending moment distribution, as shown in Figure 4.

Anchoring section shearing Q_y:

$\begin{array}{c}{Q}_y=E_{1}L-\frac{1}{6}{B}_p{\mathrm{m\&phi;y}}^2\left(3y_0-2y\right)\\ =147.2\&times;5-3\&times;4258\&times;4.2\&times;{10}^{-4}\&times;y^2\left(3\&times;11.7-2y\right)/6\\ =736-31.4y^2+1.8y^3\end{array}$

Anchoring section moment M_y:

$\begin{array}{c}{M}_y=\frac{1}{3}{E}_1{\mathrm{Lh}}_1+E_{1}Ly-\frac{1}{12}{B}_p{\mathrm{m\&phi;y}}^3\left(2y_0-y\right)\\ =147.2\&times;5\&times;8/3+147.2\&times;5y-3\&times;4258\&times;4.2\&times;{10}^{-4}\&times;y^3\left(2\&times;11.7-y\right)/12\\ =1963+736y-10.5y^3+0.45y^4\end{array}$

The calculated anchoring section maximal bending moment distance away from ground is 5.8m.

D) foundation deformation state evaluation before stake

Away from below ground (1/3) h₂The degree of depth and h₂Depth anchor pile is to ground lateral stress σ_y, result is as listed in table 3, different The σ of depth_p1With soil lateral stress σ_yAlong the anchoring section degree of depth distribution as shown in Figure 5.Calculating process is as follows:

Y=1/3h₂[the σ of depth_H ⁱ]；

Y=h₂[the σ of depth_H ⁱ]；

Table 3 ground lateral stress σ y unit: kPa

From table 3 and Fig. 5, calculated deep less than this away from below ground anchor pile each depth Pile side soil stress σ y Foundation soil lateral bearing capacity σ p1 under fast and stable state at degree, it can thus be assumed that the Sizes of intended stake, ground before wall stake Soil deformation is in fast and stable state.Control requirement by pile strength again and carry out arrangement of reinforcement calculating, complete design.

Claims (1)

1. a method for designing for ballastless track of high-speed railway stake plate type retaining wall, is carried out as follows:

(1) survey means with passing through and obtain the undisturbed soil sample of design work point foundation soil, carry out indoor triaxial test and record soil sample Intensity index c andCarry out indoor long-term triaxial test simultaneously and record the state threshold parameter lambda that fast and stable state is corresponding, without bar When part carries out indoor long-term triaxial test, λ takes 15%；

(2) it is calculated state strength parameter c of foundation soil before stake according to gained state threshold parameter lambda¹WithComputing formula is:

In formulaFoundation soil is in state strength parameter during the first state, internal friction angle, °；

c¹Foundation soil is in state strength parameter during the first state, cohesion, kPa；

Foundation soil actual strength parameter, internal friction angle, °；

C foundation soil actual strength parameter, cohesion, kPa；

λ₁It is in state threshold parameter during the first state；

(3) it is calculated the lateral bearing capacity σ of foundation soil deformation state before stake according to gained state strength parameter_p ¹, computing formula For:

σ in formula_p ¹Foundation soil is in lateral bearing capacity during the first state, kPa；

The severe of γ foundation soil, kN/m³；

Y is away from the earth's surface degree of depth, m；

(4) draft anchor pile sectional dimension and anchoring depth by traditional anchor pile design and calculation method, calculate anchor pile pair Ground earth lateral pressure σ before stake_y；

(5) σ at below ground 1/3 anchoring depth is compared_yWith σ_p ¹If, σ_y≤σ_p ¹Show that foundation soil is at the work of anchor pile before stake Do not have the deformation having time effect under with, next step design can be carried out and calculate；If σ_y>σ_p ¹Shi Zexu adjust pile spacing or The parameters such as the sectional dimension of stake recalculate, until meeting σ_y≤σ_p ¹；

(6) Reinforcement Design of anchor pile, complete design flow process are carried out.